It’s a quarter of a century since Freddie Mercury and soprano Montserrat Caballé released their hit duet Barcelona, a high-camp operatic love song to Caballé’s home city that became even more popular during the 1992 Olympics in the Catalan capital, not long after Mercury’s death from Aids in November 1991.

It was, according to some of the friends interviewed in this affectionate tribute to the flamboyant Queen frontman by director Rhys Thomas, probably the recording he was proudest of in a career of spectacular chart successes.

The film sketches in Mercury's early years with Queen, but the main emphasis is on how he strove to escape the restrictions, and expectations, of life as a member of one of the world’s foremost rock bands – whether by indulging in all that the hedonistic pre-Aids gay scene of the early Eighties had to offer, or through a series of not-entirely-successful solo musical ventures.

Stories of a collaboration with Michael Jackson, some home recordings of Mercury and Caballé rehearsing together, and contributions from band members Brian May and Roger Taylor, pal Paul Gambaccini, fan Matt Lucas and Caballé herself are among the pleasures on offer.

Freddie Mercury: the Great Pretender – an Imagine Special is on BBC One tonight at 10.35pm (N Ireland/Wales, 11.05pm)